i) Field of the Invention
This invention relates to a rechargeable electrolytic cell and to a method of charging a rechargeable electrolytic cell.
ii) Description of Prior Art
Electrolytic cells are classified as rechargeable or non-rechargeable according to whether the energy may be restored to the cell by reversing the direction of the current flow. The standard dry cell, for example, zinc carbon or alkaline cells, used in transistor radios are probably the most familiar example of the non-rechargeable type, and the lead-acid accumulators in cars and Ni-Cd cells the best known rechargeable types. Since a non-rechargeable cell has to be discarded after use, it may at first sight seem surprising that such a cell finds any application at all. However, to date rechargeable cells are inferior in a number of key ways to non-rechargeable cells. For example, the Ni-Cd cell, which is currently the only practicable alternative to the dry cells mentioned above, has at full charge only about one-tenth the stored energy of the dry cell. Furthermore there is a limit to the number of times they can be recharged. The accepted figure for the number of times that recharging is possible is about 1,000.